Tunable Electromagnetic Performance of Pt–Si–O Films in Mid‐Infrared and Microwave Spectrums

Electromagnetic performance regulation in mid‐infrared (MIR) and microwave (MW) spectrums is crucially significant, which can be achieved by heterophase introduction and structural manufacturing. In this work, Si‐O amorphous phase is introduced into Pt film by magnetron co‐sputtering technique, the film thickness is optimized by adjusting deposition time. After annealing treatment, a double‐layered structure is constructed with the migration and growth of Pt crystals, in which the lower layer is composed of Pt coarse grains while the upper layer is Si‐O amorphous phase with embedded Pt fine grains. Furthermore, due to the thickness difference, diverse kinds of structural patterns (arrays or mesh) can be obtained with the solid‐state dewetting of the lower layer. According to the increasing thickness, the infrared emissivity can decrease from 0.67 to 0.25 (8–14 μm), demonstrating a great decline of apparent temperature of 162.9 °C when the background is 300 °C. And the microwave transmissivity also exhibits tremendous variation over 90% (from 96% to 5%), realizing the transformation from transmitting to shielding.